1. Field of the Invention
The present invention relates to an optical scanning device and an image forming apparatus, and more specifically, relates to an optical scanning device that uses a light beam to scan a surface to be scanned, and an image forming apparatus that includes the optical scanning device.
2. Description of the Related Art
An image forming apparatus that employs a laser is widely employed in an electrophotographic recording of an image. In such a circumstance, a method wherein the image forming apparatus includes an optical scanning device, and forms a latent image by causing a photosensitive drum to rotate, while employing a polygon scanner, for instance, a polygon mirror, to scan a laser light in an axial direction of the drum, is typical. In such an electrophotography sector, what is demanded of the image forming apparatus is an increased density of the image, in order to improve a quality of the image, and a higher speed in an output of the image, in order to improve an operability of the image forming apparatus.
A multi-beam splitting of a light beam that is emitted from a light source is one method of balancing the increased density with the higher speed.
For instance, Japanese Patent Laid Open No. 2004-287292 discloses an optical scanning device, comprising a first substrate whereupon is incorporated a light emitting element and a driving circuit thereof, and which is attached to a housing that is anchored to a main body of a image forming apparatus, a second substrate whereupon is incorporated a connector that connects a harness from the main body of the image forming apparatus, and which is attached to the housing, physically separate from the first substrate, a terminal of the first substrate, a terminal of the second substrate, and a connection material that is capable of being elastically transformed, and which is electrically connected to the terminal of the first substrate and the terminal of the second substrate. The optical scanning device employs a surface emitting laser array as a multi-beam light source.
As another instance, Japanese Patent Laid Open No. 2005-250319 discloses a light source device that is configured by combining a plurality of an assembly of a light source wherein a plurality of light emitting points that are capable of being individually modulated are positioned two-dimensionally, and a coupling lens that couples a divergent light beam that is emitted from the light source. The light source device employs a vertical cavity surface emitting laser array as the light source.
It is to be noted, however, that when scanning a surface to be scanned with a plurality of the light beam, a beam pitch that relates to a sub or vertical scanning direction of the surface to be scanned (also to be referred to hereinafter as “sub scan beam pitch” for purposes of ease of designation) may deviate from a desired value, for instance, a design value, as a consequence of such as an error in a location of an optical element that is positioned between the light source and the surface to be scanned, or an error in a shape of the optical element thus positioned. A hazard is present wherein the deviation of the sub scan beam pitch may have a negative effect on the quality of the image with regard to a further increased density of the image that is anticipated hereinafter.